I can bs you can bs she can bs we can bs you can bs they can bs
V-ing form
I can be bsing you can be bsing she can be bsing we can be bsing you can be bsing they can be bsing
Perfect
I can have bsed you can have bsed she can have bsed we can have bsed you can have bsed they can have bsed
V-ing perfect
I can have been bsing you can have been bsing she can have been bsing we can have been bsing you can have been bsing they can have been bsing
Negation
Simple form
I cannot bs you cannot bs she cannot bs we cannot bs you cannot bs they cannot bs
V-ing form
I cannot be bsing you cannot be bsing she cannot be bsing we cannot be bsing you cannot be bsing they cannot be bsing
Perfect
I cannot have bsed you cannot have bsed she cannot have bsed we cannot have bsed you cannot have bsed they cannot have bsed
V-ing perfect
I cannot have been bsing you cannot have been bsing she cannot have been bsing we cannot have been bsing you cannot have been bsing they cannot have been bsing
Interrogative form
Simple form
can I bs? can you bs? can she bs? can we bs? can you bs? can they bs?
V-ing form
can I be bsing? can you be bsing? can she be bsing? can we be bsing? can you be bsing? can they be bsing?
Perfect
can I have bsed? can you have bsed? can she have bsed? can we have bsed? can you have bsed? can they have bsed?
V-ing perfect
can I have been bsing? can you have been bsing? can she have been bsing? can we have been bsing? can you have been bsing? can they have been bsing?
Interro-negative form
Simple form
can I not bs? can you not bs? can she not bs? can we not bs? can you not bs? can they not bs?
V-ing form
can I not be bsing? can you not be bsing? can she not be bsing? can we not be bsing? can you not be bsing? can they not be bsing?
Perfect
can I not have bsed? can you not have bsed? can she not have bsed? can we not have bsed? can you not have bsed? can they not have bsed?
V-ing perfect
can I not have been bsing? can you not have been bsing? can she not have been bsing? can we not have been bsing? can you not have been bsing? can they not have been bsing?